Carbon monoxide (abbreviated as “CO”) is an invisible, colorless, odorless gas that is produced every time fossil fuels are burned. When it is inhaled to excess, it causes serious illness, irreversible brain damage or death.

But you could have lower levels of the silent killer in your home causing flu-like symptoms, memory issues or headaches and not realize you are slowly being poisoned.

When gas- or oil-burning furnaces and water heaters are working properly, they produce small amounts of CO that are safely vented from the home, causing no health problems. But if these devices are not working properly, they may generate more CO than is safe to breathe. Because the gas can not be detected by sight or smell, the only way to know that such a dangerous condition exists is by having a working CO detectors installed in the home.

Related read: Failed heat exchanger – what you should know

 Why is CO Dangerous?

Like carbon dioxide (CO2), carbon monoxide is a byproduct of combustion. But CO is much more dangerous than CO2. Here’s why:

 When you breathe healthy air, your red blood cells absorb oxygen (O2) that your body needs to generate energy and keep your organs and tissues healthy. Unfortunately, red blood cells absorb CO at a much faster rate than they absorb O2, and if there’s too much CO in the air, it crowds out the O2 in your red blood cells. Your organs can’t use CO, though, and the effect of breathing too much of it is that your blood can’t do its job delivering oxygen to your organs. The result is pretty much the same as suffocating.

In addition to furnaces and water heaters, CO-producing devices in the home may include wood stoves, standby generators, and other devices that should not be used in enclosed spaces, like portable kerosene heaters,generators and motor vehicles.

Who Does Carbon Monoxide Affect?

Between 1999 and 2010, according to the Centers for Disease Control and Prevention, there were 5,149 deaths in the United States attributed to unintentional carbon monoxide poisoning. That is an average of 430 deaths per year. The death rate for males was three times higher than for females – possibly because they are more likely to work on cars or use fuel-burning equipment in enclosed spaces.

Death rates also differed by age group. They were highest for people aged 65 or greater, and lowest for people aged 25-years or less, mainly because younger people tend to have healthier lungs and hearts.

Those who live alone are particularly susceptible to CO poisoning, often because they are not aware they are being affected, and there is no one near to notice the symptoms. Carbon monoxide poisoning is especially dangerous for people when they are sleeping or intoxicated, again because the symptoms go unnoticed for too long.

CO Poisoning Symptoms and Response

The symptoms of carbon monoxide poisoning are:

  • dull headache
  • weakness
  • dizziness
  • nausea or vomiting
  • confusion
  • blurred vision
  • loss of consciousness

The warning signs may be subtle at times, but make no mistake: carbon monoxide poisoning is a life-threatening medical emergency. If you or someone you know is being affected by carbon monoxide poisoning, immediately exit the home or building, go outside into fresh air, and then seek emergency medical care. Have an expert assess the air quality in the home before you reenter it.

Preventing CO Poisoning

Having working CO monitors in the home is the most important step you can take to prevent carbon monoxide poisoning. One should be installed on every level, including – especially – the basement, if that’s where the furnace or water heater is located. Replace the batteries every year, and replace the detectors on the schedule recommended by the manufacturer, because they do not last indefinitely.


Also important is to make sure your furnace, water heater and other fuel-burning devices in the home are working correctly. This means that they are burning fuel efficiently, so as not to produce excessive waste products like CO and CO2, and that they are venting gases safely outside the building.

Experts in furnace repair and maintenance are qualified to determine if your furnace is working correctly and to make the necessary repairs or adjustments to keep it that way.

Related read: Why you need a maintenance program for your furnace, A/C

Home Comfort Experts offers heating system service, repairs and installation in northern Indiana and southwestern Michigan. If you haven’t had your furnace and water heater inspected in more than a year or have other concerns about carbon monoxide in your home, please give us a call at (574) 255-4600 to schedule service.

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